When ubiquitin meets ubiquitin receptors: a signalling connection

Abstract
Ubiquitylation is emerging as a versatile device for controlling cellular functions. Here, we propose that monoubiquitylation is rapidly induced by signalling events and allows the establishment of protein–protein interactions between monoubiquitylated proteins and partners that contain distinct ubiquitin-binding domains. We also put forward speculative models for the regulation of monoubiquitylation versus polyubiquitylation.